SmartClockPi

8/6/25

Update 1

Started a new project for a smart clock using the Raspberry Pi Zero 2 W.

Planning: - Decided on a feature set: large touchscreen display, temperature/humidity/pressure monitoring, internet weather, touch sensing, and music playback for the alarm part. - Researched and compared display modules -- settled on a 3.5" ILI9488 SPI TFT resistive touchscreen (480x320). Good size and clarity. - Chose the BME280 sensor for environmental data, using the I2C interface with the Pi and freeing SPI for the display. - Support for both devices with available Python libraries (luma.lcd, Pillow, adafruit-circuitpython-bme280). (at least I hope so)

Links:
- 3.5" ILI9488 SPI TFT Touch Display
- BME280 I2C/SPI Sensor Module

Hardware & Wiring:
Used the pinout provided in the datasheet for the display:

The BME280:

SPI Display Pins (ILI9488)

Pin	Name	Description	Raspberry Pi Zero 2 W Pin
1	VCC	5V/3.3V power input	3.3V (Pin 1 or 17)
2	GND	grounding	GND (Pin 6 or 9)
3	CS	LCD chip select signal, low level enable	GPIO8 (SPI0_CE0, Pin 24)
4	RESET	LCD reset signal, low level reset	GPIO25 (Pin 22)
5	DC/RS	LCD register/data selection signal	GPIO24 (Pin 18)
6	SDI(MOSI)	SPI bus write data signal	GPIO10 (SPI0_MOSI, Pin 19)
7	SCK	SPI bus clock signal	GPIO11 (SPI0_SCLK, Pin 23)
8	LED	Backlight control (tie to 3.3V for always on)	3.3V (Pin 1 or 17)
9	SDO(MISO)	SPI bus read data signal (optional)	GPIO9 (SPI0_MISO, Pin 21)

Touch Panel Pins (using touch, XPT2046 controller)

Pin	Name	Description	Raspberry Pi GPIO (need to work this out later)
10	T_CLK	Touch SPI bus clock signal	Any free GPIO
11	T_CS	Touch chip select (active low)	Any free GPIO
12	T_DIN	Touch SPI input	Any free GPIO
13	T_DO	Touch SPI output	Any free GPIO
14	T_IRQ	Touch interrupt (active low)	Any free GPIO

BME280 Sensor (I2C)

Pin	Name	Description	Raspberry Pi Zero 2 W Pin
1	VCC	3.3V power	3.3V (Pin 1 or 17)
2	GND	Ground	GND (Pin 6 or 9)
3	SDA	I2C data	GPIO2 (I2C SDA, Pin 3)
4	SCL	I2C clock	GPIO3 (I2C SCL, Pin 5)

• Both modules use 3.3V power (chose BME-3.3, so do NOT use 5V).
• LED pin on display can be tied to 3.3V for always-on backlight, or controlled by a PWM GPIO for dimming.

TO_DO - add a photoresistor or something to chnage the bightness dynamically

Time spent today: 2 hours (research, planning, reviewing libraries, looking for modules, and mapping out wiring)

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10/6/25

Update 2

Worked on SmartClockPi code and UI, even though I don't have the hardware yet.

Today: - Wrote the main Python app logic for the clock display and sensor/weather integration. - Used the luma.lcd library for the ILI9488 SPI display, and adafruit-circuitpython-bme280 for the sensor interface. - Integrated free weather data from wttr.in for Auckland, Half Moon Bay area (no API key required). - The app will show:
- Real time and date (large, clear fonts) - Indoor temperature, humidity, and pressure (from BME280, once connected) - Outdoor weather: main status, temperature, humidity, and icon (from wttr.in) - Weather auto-refreshes every 10 minutes, sensor data every second. - Alarm logic is removed for now to keep the code simple. - All code is structured to be ready for testing as soon as the display and sensors are available. - Next steps: add touch UI, dynamic backlight (photoresistor), and maybe a settings menu.

Time spent this session: 1.5 hours

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Update 3

I started working on the schematic for the project. I wanted to include both the Raspberry Pi header, the BME280 sensor, and the ILI9488 touchscreen display in my design. However, I ran into an issue: I couldn't find a suitable symbol or footprint for the LCD screen I’m using (the ILI9488 SPI TFT touchscreen) in my KiCad’s library.

I decided to use generic header pins to represent the LCD screen in the schematic. This way, I was able to clearly show all of the required connections for the display, including the SPI and touch controller signals, power, and backlight control.

When i get the PCB, I will just solder some female header pins (1x14) onto the board, and plug the screen in. I might need some standoffs though...

Next step: add in a photoresistor

Time spent this session: 3 hours

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11/6/25

Update 4

I finalised my schematic during the session. The main challenge is to find the footprints and symbols for my parts. I ended up using female header pins to plug my modules in.

Time spent this session: 5 hours

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12/6/25

Update 5

Started working on the PCB. It was very stupid converting the schematics into PCB. The Tools > Update PCB from schematics was greyed out. But somehow I made it work after wasting a lot of time...

Time spent this session: 4 hours

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14/5/25 & 15/5/25

Update 6

Started sourcing the parts and organising them into a spreadsheet/Excel document

(note there are a lot of mistakes - 16/6/25)

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13/5/25 & 16/5/25

Update 7

Did a lot of work on the PCB. I connected all my 17 parts (at the time of writing) together. The big, main issue I had was to get the blue wires (connector lines) to show up on some of the parts. Turned out KiCad didn't know which pins were which, so it ignored them. I changed the pin numbers from correct ones to lables, replacing the numbers, since I couldn't make the lables show up before. So I changed the pin numbers back, and YAY!!

The PCB is done, so long as I don't decide to drop a few more parts in....

Time spent this session: 6 hours

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17/5/25

Update 8

Added my parts to my BOM. I started to source some of the parts, including the Raspberry Pi Zero 2 ($25 before, now $15!!)

Time spent this session: 1.5 hours

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18/5/25

Update 9

For this session, I worked more on the PCB. Unfortunately, I did change the PCB layout to make way for the USB connectors. The connectors are for the Li-ion battery charger module. Since there is an extra USB output, I connected it to the PCB, providing 2.4A at 5V QC.

Sourcing the USB ports was very annoying, especially with the microUSB ports (there are so many different kinds!!)

Time spent this session: 2.5 hours